EP1013 Overview of non-epithelial ovarian tumours: incidence and survival in the netherlands

Introduction/Background About 5% of ovarian tumours have a non-epithelial histology, including germ cell tumours (GCTs), sex cord-stromal tumours (SCSTs), and sarcomas. Since the rarity of these non-epithelial ovarian tumours and the scarcity of population-based studies, the aim of this population-based study is to describe trends in incidence, treatment, and survival of these women in the Netherlands. Methodology All Dutch women diagnosed with non-epithelial ovarian malignant tumours between 1989 and 2015 were identified from the Netherlands Cancer Registry. Demographics, tumour characteristics, and initial treatment were collected and overall survival was analysed. Results A total of 1258 women were diagnosed with non-epithelial ovarian tumours in the Netherlands, including 752 GCTs (60%), 341 SCSTs (27%), and 165 sarcomas (13%). The European age standardized incidence rate (ESR) was 0.4 per 100,000 persons per year for GCTs, 0.2 for SCSTs and 0.1 for sarcomas. Approximately 97% of patients underwent surgical resection for the primary tumour, whereas 31% received systemic treatment and 3% radiotherapy. Five-year overall survival improved for all histologic subtypes between the late 1980’s until 2015: GCTs from 73% to 88% (p=0.03) SCSTs from 64% to 81% (p=0.57) and sarcomas from 20% to 29% (p=0.14). Conclusion Malignant GCTs and SCSTs are rare and its incidence did not significantly change during the last decades. They have a good prognosis which also improved slightly. Women with primary sarcomas of the ovary are extremely rare and still have a poor prognosis. Disclosure Nothing to disclose.